When comparing ShiftIt vs Byword, the Slant community recommends Byword for most people. In the question“What are the best power user tools for macOS?”Byword is ranked 35th while ShiftIt is ranked 41st. The most important reason people chose Byword is:

Byword de-emphasizes the syntax itself, while emphasizing its effects. It appropriately adds style, like italic and bold, to text that's designated by markdown and dims the syntax so it does not getting in the way of comprehension. Additionally, there are commonly used hotkeys (⌘b, ⌘i, etc) that can be used to apply style without having to know the syntax or having to type it out each time.

Pros

Pro

Easy to configure

ShiftIt is configured through a simple UI where you simply press the hotkeys you wish to map to a certain action.

Pro

Free

Pro

Open source

Pro

Intuitive

ShiftIt is very straight-forward to use for most frequent usages.

Pro

Exemplary Markdown support

Byword de-emphasizes the syntax itself, while emphasizing its effects. It appropriately adds style, like italic and bold, to text that's designated by markdown and dims the syntax so it does not getting in the way of comprehension. Additionally, there are commonly used hotkeys (⌘b, ⌘i, etc) that can be used to apply style without having to know the syntax or having to type it out each time.

Pro

Includes features that speed up writing

For example, while authoring a bulleted list hitting return automatically prepares a new bulleted line.

Pro

Available for all Apple devices

Byword is available on a Mac, an iPhone and an iPad.

Pro

Syncs using iCloud and Dropbox

Documents can be synced using iCloud or Dropbox from within the editor for use across all devices.

Pro

Word count support

Pro

A dark theme is available

Pro

Can publish directly to external services

Pro

Can export to html, pdf, rtf

In addition to plaintext, Byword can export to HTML, PDF, RTF.

Pro

Live update support

Cons

Con

Doesn't support moving windows between workspaces

There's no way to move a window to a different workspace with hotkeys in ShiftIt.